MDMD(11): That Great Moment of Clarity

[Dave Monroe]

"'I have come to believe, that Maskelyne lingers only
because Bradley discover'd the Aberration, and
achiev'd
Glory, whilst trying to find the Parallax of London's
Zenith Star.  Might not that great moment of Clarity
beneath Draco, reasons Maskelyne, be repeated there,
beneath the Great Dog?'" (M&D, Ch. 17, p. 181)

>From Tim Ware's HyperArts Pynchon Pages ...

http://www.hyperarts.com/pynchon/index.html

"In 1725 James Bradley, an English amateur astronomer,
was attempting to observe stellar parallax when,
through meticulous observation he observed that stars
did trace out small ellipses in the sky as expected
for parallax, but that all stars traced out precisely
the same ellipses! This didn't make any sense at all;
the only way the parallax of all stars could be same
would be if all the stars were the same distance from
the Earth--a regression to the Earth-centred universe
with a vengeance! After a while, the apparent motion
Bradley observed was discovered to be the result of
the aberration of light. On each point in its orbit,
the Earth is travelling with a velocity with respect
to the distant stars that differs by 60 kilometers per
second from the velocity at the opposing point--where
the Earth will be six months hence. 

"Now 60 kilometers a second is pretty fast compared to
freeway speed limits or even the velocity of Earth
satellites, but it's only 0.02% of the speed of light.
However, by Bradley's time the art and science of
measuring the positions of stars had advanced to such
an extent that he was able to observe the mere 41
arc-second displacement of the apparent position of
stars due to aberration. 

"It wasn't until 1837 that astronomers managed to
measure the much smaller parallax of the nearest
stars. The classical aberration of light discovered by
Bradley must be taken into account whenever accurate
positions of objects in the sky are calculated."

http://www.hyperarts.com/pynchon/mason-dixon/extra/info.html

Courtesy, apparently, of one John Walker ...

http://www.fourmilab.ch/cship/aberration.html

But y'all seem astronomically and/or astrologically
inclined, any ideas on Draco, the Dragon ...

http://www.hawastsoc.org/deepsky/dra/index.html

http://www.seds.org/Maps/Stars_en/Fig/draco.html

Vs. Canis Major, the Great Dog ...

http://www.hawastsoc.org/deepsky/cma/index.html

http://www.seds.org/Maps/Stars_en/Fig/canismajor.html

As Sirius looms o'er our semiotic horizon once again? 
Again, let me know ...



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